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<?php

/**

 * @file

 * Definition of FeedsSourceInterface and FeedsSource class.

 */

/**

 * Distinguish exceptions occuring when handling locks.

 */

class FeedsLockException extends Exception {}

/**

 * Denote a import or clearing stage. Used for multi page processing.

 */

define('FEEDS_START', 'start_time');

define('FEEDS_FETCH', 'fetch');

define('FEEDS_PARSE', 'parse');

define('FEEDS_PROCESS', 'process');

define('FEEDS_PROCESS_CLEAR', 'process_clear');

/**

 * Declares an interface for a class that defines default values and form

 * descriptions for a FeedSource.

 */

interface FeedsSourceInterface {

  /**

   * Crutch: for ease of use, we implement FeedsSourceInterface for every

   * plugin, but then we need to have a handle which plugin actually implements

   * a source.

   *

   * @see FeedsPlugin class.

   *

   * @return

   *   TRUE if a plugin handles source specific configuration, FALSE otherwise.

   */

  public function hasSourceConfig();

  /**

   * Return an associative array of default values.

   */

  public function sourceDefaults();

  /**

   * Return a Form API form array that defines a form configuring values. Keys

   * correspond to the keys of the return value of sourceDefaults().

   */

  public function sourceForm($source_config);

  /**

   * Validate user entered values submitted by sourceForm().

   */

  public function sourceFormValidate(&$source_config);

  /**

   * A source is being saved.

   */

  public function sourceSave(FeedsSource $source);

  /**

   * A source is being deleted.

   */

  public function sourceDelete(FeedsSource $source);

}

/**

 * Status of an import or clearing operation on a source.

 */

class FeedsState {

  /**

   * Floating point number denoting the progress made. 0.0 meaning no progress

   * 1.0 = FEEDS_BATCH_COMPLETE meaning finished.

   */

  public $progress;

  /**

   * Used as a pointer to store where left off. Must be serializable.

   */

  public $pointer;

  /**

   * Natural numbers denoting more details about the progress being made.

   */

  public $total;

  public $created;

  public $updated;

  public $deleted;

  public $skipped;

  public $failed;

  /**

   * Constructor, initialize variables.

   */

  public function __construct() {

    $this->progress = FEEDS_BATCH_COMPLETE;

    $this->total =

    $this->created =

    $this->updated =

    $this->deleted =

    $this->skipped =

    $this->failed = 0;

  }

  /**

   * Safely report progress.

   *

   * When $total == $progress, the state of the task tracked by this state is

   * regarded to be complete.

   *

   * Handles the following cases gracefully:

   *

   * - $total is 0

   * - $progress is larger than $total

   * - $progress approximates $total so that $finished rounds to 1.0

   *

   * @param $total

   *   A natural number that is the total to be worked off.

   * @param $progress

   *   A natural number that is the progress made on $total.

   */

  public function progress($total, $progress) {

    if ($progress > $total) {

      $this->progress = FEEDS_BATCH_COMPLETE;

    }

    elseif ($total) {

      $this->progress = $progress / $total;

      if ($this->progress == FEEDS_BATCH_COMPLETE && $total != $progress) {

        $this->progress = 0.99;

      }

    }

    else {

      $this->progress = FEEDS_BATCH_COMPLETE;

    }

  }

}

/**

 * This class encapsulates a source of a feed. It stores where the feed can be

 * found and how to import it.

 *

 * Information on how to import a feed is encapsulated in a FeedsImporter object

 * which is identified by the common id of the FeedsSource and the

 * FeedsImporter. More than one FeedsSource can use the same FeedsImporter

 * therefore a FeedsImporter never holds a pointer to a FeedsSource object, nor

 * does it hold any other information for a particular FeedsSource object.

 *

 * Classes extending FeedsPlugin can implement a sourceForm to expose

 * configuration for a FeedsSource object. This is for instance how FeedsFetcher

 * exposes a text field for a feed URL or how FeedsCSVParser exposes a select

 * field for choosing between colon or semicolon delimiters.

 *

 * It is important that a FeedsPlugin does not directly hold information about

 * a source but leave all storage up to FeedsSource. An instance of a

 * FeedsPlugin class only exists once per FeedsImporter configuration, while an

 * instance of a FeedsSource class exists once per feed_nid to be imported.

 *

 * As with FeedsImporter, the idea with FeedsSource is that it can be used

 * without actually saving the object to the database.

 */

class FeedsSource extends FeedsConfigurable {

  // Contains the node id of the feed this source info object is attached to.

  // Equals 0 if not attached to any node - i. e. if used on a

  // standalone import form within Feeds or by other API users.

  protected $feed_nid;

  // The FeedsImporter object that this source is expected to be used with.

  protected $importer;

  // A FeedsSourceState object holding the current import/clearing state of this

  // source.

  protected $state;

  // Fetcher result, used to cache fetcher result when batching.

  protected $fetcher_result;

  // Timestamp when this source was imported the last time.

  protected $imported;

  /**

   * Instantiate a unique object per class/id/feed_nid. Don't use

   * directly, use feeds_source() instead.

   */

  public static function instance($importer_id, $feed_nid) {

    $class = variable_get('feeds_source_class', 'FeedsSource');

    static $instances = array();

    if (!isset($instances[$class][$importer_id][$feed_nid])) {

      $instances[$class][$importer_id][$feed_nid] = new $class($importer_id, $feed_nid);

    }

    return $instances[$class][$importer_id][$feed_nid];

  }

  /**

   * Constructor.

   */

  protected function __construct($importer_id, $feed_nid) {

    $this->feed_nid = $feed_nid;

    $this->importer = feeds_importer($importer_id);

    parent::__construct($importer_id);

    $this->load();

  }

  /**

   * Returns the FeedsImporter object that this source is expected to be used with.

   */

  public function importer() {

    return $this->importer;

  }

  /**

   * Preview = fetch and parse a feed.

   *

   * @return

   *   FeedsParserResult object.

   *

   * @throws

   *   Throws Exception if an error occurs when fetching or parsing.

   */

  public function preview() {

    $result = $this->importer->fetcher->fetch($this);

    $result = $this->importer->parser->parse($this, $result);

    module_invoke_all('feeds_after_parse', $this, $result);

    return $result;

  }

  /**

   * Start importing a source.

   *

   * This method starts an import job. Depending on the configuration of the

   * importer of this source, a Batch API job or a background job with Job

   * Scheduler will be created.

   *

   * @throws Exception

   *   If processing in background is enabled, the first batch chunk of the

   *   import will be executed on the current page request. This means that this

   *   method may throw the same exceptions as FeedsSource::import().

   */

  public function startImport() {

    module_invoke_all('feeds_before_import', $this);

    $config = $this->importer->getConfig();

    if ($config['process_in_background']) {

      $this->startBackgroundJob('import');

    }

    else {

      $this->startBatchAPIJob(t('Importing'), 'import');

    }

  }

  /**

   * Start deleting all imported items of a source.

   *

   * This method starts a clear job. Depending on the configuration of the

   * importer of this source, a Batch API job or a background job with Job

   * Scheduler will be created.

   *

   * @throws Exception

   *   If processing in background is enabled, the first batch chunk of the

   *   clear task will be executed on the current page request. This means that

   *   this method may throw the same exceptions as FeedsSource::clear().

   */

  public function startClear() {

    $config = $this->importer->getConfig();

    if ($config['process_in_background']) {

      $this->startBackgroundJob('clear');

    }

    else {

      $this->startBatchAPIJob(t('Deleting'), 'clear');

    }

  }

  /**

   * Schedule all periodic tasks for this source.

   */

  public function schedule() {

    $this->scheduleImport();

  }

  /**

   * Schedule periodic or background import tasks.

   */

  public function scheduleImport() {

    // Check whether any fetcher is overriding the import period.

    $period = $this->importer->config['import_period'];

    $fetcher_period = $this->importer->fetcher->importPeriod($this);

    if (is_numeric($fetcher_period)) {

      $period = $fetcher_period;

    }

    $period = $this->progressImporting() === FEEDS_BATCH_COMPLETE ? $period : 0;

    $job = array(

      'type' => $this->id,

      'id' => $this->feed_nid,

      // Schedule as soon as possible if a batch is active.

      'period' => $period,

      'periodic' => TRUE,

    );

    if ($period != FEEDS_SCHEDULE_NEVER) {

      JobScheduler::get('feeds_source_import')->set($job);

    }

    else {

      JobScheduler::get('feeds_source_import')->remove($job);

    }

  }

  /**

   * Schedule background clearing tasks.

   */

  public function scheduleClear() {

    $job = array(

      'type' => $this->id,

      'id' => $this->feed_nid,

      'period' => 0,

      'periodic' => TRUE,

    );

    // Remove job if batch is complete.

    if ($this->progressClearing() === FEEDS_BATCH_COMPLETE) {

      JobScheduler::get('feeds_source_clear')->remove($job);

    }

    // Schedule as soon as possible if batch is not complete.

    else {

      JobScheduler::get('feeds_source_clear')->set($job);

    }

  }

  /**

   * Import a source: execute fetching, parsing and processing stage.

   *

   * This method only executes the current batch chunk, then returns. If you are

   * looking to import an entire source, use FeedsSource::startImport() instead.

   *

   * @return

   *   FEEDS_BATCH_COMPLETE if the import process finished. A decimal between

   *   0.0 and 0.9 periodic if import is still in progress.

   *

   * @throws

   *   Throws Exception if an error occurs when importing.

   */

  public function import() {

    $this->acquireLock();

    try {

      // If fetcher result is empty, we are starting a new import, log.

      if (empty($this->fetcher_result)) {

        $this->state[FEEDS_START] = time();

      }

      // Fetch.

      if (empty($this->fetcher_result) || FEEDS_BATCH_COMPLETE == $this->progressParsing()) {

        $this->fetcher_result = $this->importer->fetcher->fetch($this);

        // Clean the parser's state, we are parsing an entirely new file.

        unset($this->state[FEEDS_PARSE]);

      }

      // Parse.

      $parser_result = $this->importer->parser->parse($this, $this->fetcher_result);

      module_invoke_all('feeds_after_parse', $this, $parser_result);

      // Process.

      $this->importer->processor->process($this, $parser_result);

    }

    catch (Exception $e) {

      // Do nothing.

    }

    $this->releaseLock();

    // Clean up.

    $result = $this->progressImporting();

    if ($result == FEEDS_BATCH_COMPLETE || isset($e)) {

      $this->imported = time();

      $this->log('import', 'Imported in !s s', array('!s' => $this->imported - $this->state[FEEDS_START]), WATCHDOG_INFO);

      module_invoke_all('feeds_after_import', $this);

      unset($this->fetcher_result, $this->state);

    }

    $this->save();

    if (isset($e)) {

      throw $e;

    }

    return $result;

  }

  /**

   * Remove all items from a feed.

   *

   * This method only executes the current batch chunk, then returns. If you are

   * looking to delete all items of a source, use FeedsSource::startClear()

   * instead.

   *

   * @return

   *   FEEDS_BATCH_COMPLETE if the clearing process finished. A decimal between

   *   0.0 and 0.9 periodic if clearing is still in progress.

   *

   * @throws

   *   Throws Exception if an error occurs when clearing.

   */

  public function clear() {

    $this->acquireLock();

    try {

      $this->importer->fetcher->clear($this);

      $this->importer->parser->clear($this);

      $this->importer->processor->clear($this);

    }

    catch (Exception $e) {

      // Do nothing.

    }

    $this->releaseLock();

    // Clean up.

    $result = $this->progressClearing();

    if ($result == FEEDS_BATCH_COMPLETE || isset($e)) {

      module_invoke_all('feeds_after_clear', $this);

      unset($this->state);

    }

    $this->save();

    if (isset($e)) {

      throw $e;

    }

    return $result;

  }

  /**

   * Report progress as float between 0 and 1. 1 = FEEDS_BATCH_COMPLETE.

   */

  public function progressParsing() {

    return $this->state(FEEDS_PARSE)->progress;

  }

  /**

   * Report progress as float between 0 and 1. 1 = FEEDS_BATCH_COMPLETE.

   */

  public function progressImporting() {

    $fetcher = $this->state(FEEDS_FETCH);

    $parser = $this->state(FEEDS_PARSE);

    if ($fetcher->progress == FEEDS_BATCH_COMPLETE && $parser->progress == FEEDS_BATCH_COMPLETE) {

      return FEEDS_BATCH_COMPLETE;

    }

    // Fetching envelops parsing.

    // @todo: this assumes all fetchers neatly use total. May not be the case.

    $fetcher_fraction = $fetcher->total ? 1.0 / $fetcher->total : 1.0;

    $parser_progress = $parser->progress * $fetcher_fraction;

    $result = $fetcher->progress - $fetcher_fraction + $parser_progress;

    if ($result == FEEDS_BATCH_COMPLETE) {

      return 0.99;

    }

    return $result;

  }

  /**

   * Report progress on clearing.

   */

  public function progressClearing() {

    return $this->state(FEEDS_PROCESS_CLEAR)->progress;

  }

  /**

   * Return a state object for a given stage. Lazy instantiates new states.

   *

   * @todo Rename getConfigFor() accordingly to config().

   *

   * @param $stage

   *   One of FEEDS_FETCH, FEEDS_PARSE, FEEDS_PROCESS or FEEDS_PROCESS_CLEAR.

   *

   * @return

   *   The FeedsState object for the given stage.

   */

  public function state($stage) {

    if (!is_array($this->state)) {

      $this->state = array();

    }

    if (!isset($this->state[$stage])) {

      $this->state[$stage] = new FeedsState();

    }

    return $this->state[$stage];

  }

  /**

   * Count items imported by this source.

   */

  public function itemCount() {

    return $this->importer->processor->itemCount($this);

  }

  /**

   * Save configuration.

   */

  public function save() {

    // Alert implementers of FeedsSourceInterface to the fact that we're saving.

    foreach ($this->importer->plugin_types as $type) {

      $this->importer->$type->sourceSave($this);

    }

    $config = $this->getConfig();

    // Store the source property of the fetcher in a separate column so that we

    // can do fast lookups on it.

    $source = '';

    if (isset($config[get_class($this->importer->fetcher)]['source'])) {

      $source = $config[get_class($this->importer->fetcher)]['source'];

    }

    $object = array(

      'id' => $this->id,

      'feed_nid' => $this->feed_nid,

      'imported' => $this->imported,

      'config' => $config,

      'source' => $source,

      'state' => isset($this->state) ? $this->state : FALSE,

      'fetcher_result' => isset($this->fetcher_result) ? $this->fetcher_result : FALSE,

    );

    if (db_query_range("SELECT 1 FROM {feeds_source} WHERE id = :id AND feed_nid = :nid", 0, 1, array(':id' => $this->id, ':nid' => $this->feed_nid))->fetchField()) {

      drupal_write_record('feeds_source', $object, array('id', 'feed_nid'));

    }

    else {

      drupal_write_record('feeds_source', $object);

    }

  }

  /**

   * Load configuration and unpack.

   *

   * @todo Patch CTools to move constants from export.inc to ctools.module.

   */

  public function load() {

    if ($record = db_query("SELECT imported, config, state, fetcher_result FROM {feeds_source} WHERE id = :id AND feed_nid = :nid", array(':id' => $this->id, ':nid' => $this->feed_nid))->fetchObject()) {

      // While FeedsSource cannot be exported, we still use CTool's export.inc

      // export definitions.

      ctools_include('export');

      $this->export_type = EXPORT_IN_DATABASE;

      $this->imported = $record->imported;

      $this->config = unserialize($record->config);

      if (!empty($record->state)) {

        $this->state = unserialize($record->state);

      }

      if (!is_array($this->state)) {

        $this->state = array();

      }

      if (!empty($record->fetcher_result)) {

        $this->fetcher_result = unserialize($record->fetcher_result);

      }

    }

  }

  /**

   * Delete configuration. Removes configuration information

   * from database, does not delete configuration itself.

   */

  public function delete() {

    // Alert implementers of FeedsSourceInterface to the fact that we're

    // deleting.

    foreach ($this->importer->plugin_types as $type) {

      $this->importer->$type->sourceDelete($this);

    }

    db_delete('feeds_source')

      ->condition('id', $this->id)

      ->condition('feed_nid', $this->feed_nid)

      ->execute();

    // Remove from schedule.

    $job = array(

      'type' => $this->id,

      'id' => $this->feed_nid,

    );

    JobScheduler::get('feeds_source_import')->remove($job);

  }

  /**

   * Only return source if configuration is persistent and valid.

   *

   * @see FeedsConfigurable::existing().

   */

  public function existing() {

    // If there is no feed nid given, there must be no content type specified.

    // If there is a feed nid given, there must be a content type specified.

    // Ensure that importer is persistent (= defined in code or DB).

    // Ensure that source is persistent (= defined in DB).

    if ((empty($this->feed_nid) && empty($this->importer->config['content_type'])) ||

        (!empty($this->feed_nid) && !empty($this->importer->config['content_type']))) {

      $this->importer->existing();

      return parent::existing();

    }

    throw new FeedsNotExistingException(t('Source configuration not valid.'));

  }

  /**

   * Returns the configuration for a specific client class.

   *

   * @param FeedsSourceInterface $client

   *   An object that is an implementer of FeedsSourceInterface.

   *

   * @return

   *   An array stored for $client.

   */

  public function getConfigFor(FeedsSourceInterface $client) {

    $class = get_class($client);

    return isset($this->config[$class]) ? $this->config[$class] : $client->sourceDefaults();

  }

  /**

   * Sets the configuration for a specific client class.

   *

   * @param FeedsSourceInterface $client

   *   An object that is an implementer of FeedsSourceInterface.

   * @param $config

   *   The configuration for $client.

   *

   * @return

   *   An array stored for $client.

   */

  public function setConfigFor(FeedsSourceInterface $client, $config) {

    $this->config[get_class($client)] = $config;

  }

  /**

   * Return defaults for feed configuration.

   */

  public function configDefaults() {

    // Collect information from plugins.

    $defaults = array();

    foreach ($this->importer->plugin_types as $type) {

      if ($this->importer->$type->hasSourceConfig()) {

        $defaults[get_class($this->importer->$type)] = $this->importer->$type->sourceDefaults();

      }

    }

    return $defaults;

  }

  /**

   * Override parent::configForm().

   */

  public function configForm(&$form_state) {

    // Collect information from plugins.

    $form = array();

    foreach ($this->importer->plugin_types as $type) {

      if ($this->importer->$type->hasSourceConfig()) {

        $class = get_class($this->importer->$type);

        $config = isset($this->config[$class]) ? $this->config[$class] : array();

        $form[$class] = $this->importer->$type->sourceForm($config);

        $form[$class]['#tree'] = TRUE;

      }

    }

    return $form;

  }

  /**

   * Override parent::configFormValidate().

   */

  public function configFormValidate(&$values) {

    foreach ($this->importer->plugin_types as $type) {

      $class = get_class($this->importer->$type);

      if (isset($values[$class]) && $this->importer->$type->hasSourceConfig()) {

        $this->importer->$type->sourceFormValidate($values[$class]);

      }

    }

  }

  /**

   * Writes to feeds log.

   */

  public function log($type, $message, $variables = array(), $severity = WATCHDOG_NOTICE) {

    feeds_log($this->id, $this->feed_nid, $type, $message, $variables, $severity);

  }

  /**

   * Background job helper. Starts a background job using Job Scheduler.

   *

   * Execute the first batch chunk of a background job on the current page load,

   * moves the rest of the job processing to a cron powered background job.

   *

   * Executing the first batch chunk is important, otherwise, when a user

   * submits a source for import or clearing, we will leave her without any

   * visual indicators of an ongoing job.

   *

   * @see FeedsSource::startImport().

   * @see FeedsSource::startClear().

   *

   * @param $method

   *   Method to execute on importer; one of 'import' or 'clear'.

   *

   * @throws Exception $e

   */

  protected function startBackgroundJob($method) {

    if (FEEDS_BATCH_COMPLETE != $this->$method()) {

      $job = array(

        'type' => $this->id,

        'id' => $this->feed_nid,

        'period' => 0,

        'periodic' => FALSE,

      );

      JobScheduler::get("feeds_source_{$method}")->set($job);

    }

  }

  /**

   * Batch API helper. Starts a Batch API job.

   *

   * @see FeedsSource::startImport().

   * @see FeedsSource::startClear().

   * @see feeds_batch()

   *

   * @param $title

   *   Title to show to user when executing batch.

   * @param $method

   *   Method to execute on importer; one of 'import' or 'clear'.

   */

  protected function startBatchAPIJob($title, $method) {

    $batch = array(

      'title' => $title,

      'operations' => array(

        array('feeds_batch', array($method, $this->id, $this->feed_nid)),

      ),

      'progress_message' => '',

    );

    batch_set($batch);

  }

  /**

   * Acquires a lock for this source.

   *

   * @throws FeedsLockException

   *   If a lock for the requested job could not be acquired.

   */

  protected function acquireLock() {

    if (!lock_acquire("feeds_source_{$this->id}_{$this->feed_nid}", 60.0)) {

      throw new FeedsLockException(t('Cannot acquire lock for source @id / @feed_nid.', array('@id' => $this->id, '@feed_nid' => $this->feed_nid)));

    }

  }

  /**

   * Releases a lock for this source.

   */

  protected function releaseLock() {

    lock_release("feeds_source_{$this->id}_{$this->feed_nid}");

  }

}